package day07;

import java.util.Random;

public class VerificationCode {
    public static void main(String[] args) {
        String code=generateVeriCode(4);
        System.out.println("验证码:"+code);
    }
    public static  String generateVeriCode(int len){
        String code="";
        char [] chs={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o', 'p',
                     'q','r','s','t','u','v','w','x', 'y','z','A','B','C','D', 'E','F',
                     'G','H','I', 'J','K','L','M', 'N','O','P','Q','R','S', 'T','U','V',
                     'W','X','Y','Z','0','1','2','3','4','5','6','7','8','9'};
        Random rand=new Random();
        for (int i=1;i<=len;i++){
            //int index=(int) (Math.random()*chs.length);
            int index=rand.nextInt(chs.length);
            code+=chs[index];
        }
        return code;
    }
}
